The Parker Solar Probe is getting closer to our star than any vehicle has before

In the wee hours of Saturday morning, a car-sized NASA spacecraft will embark on its journey to the center of our Solar System, where it will mingle with the scorching hot atmosphere of our Sun. The vehicle is the Parker Solar Probe, and it’s destined to get within 4 million miles of our parent star, which is closer than any other human-made artifact has reached before. From this vantage point, the probe is poised to solve mysteries about the Sun and its atmosphere that have plagued scientists for over half a century.

NASA has long wanted to send a vehicle to the Sun’s atmosphere, but such a mission has been considered impossible until the last few decades. This region of space, known as the corona, is filled with tiny, energetic particles that can reach above 3 million degrees Fahrenheit. Any vehicle that ventures near this region must have sophisticated protection to keep from melting. But thanks to advancements in carbon manufacturing and other key areas of engineering, NASA has been able to create a vehicle with a state-of-the-art heat shield and other crucial cooling systems. The result: the spacecraft will stay at room temperature in some of the hottest places in the Solar System.

The Sun’s corona is actually 300 times hotter than the surface of the Sun, and no one understands why. “If you think about walking away from a heat source or a campfire, you don’t suddenly get hotter. You get colder,” Nicola Fox, the project scientist for the Parker Solar Probe mission at Johns Hopkins University, tells The Verge. “So why does this happen?” The region gets so hot that chunks of the corona actually accelerate and break away from the immense pull of the Sun at supersonic speeds. These so-called solar winds shoot highly energized particles out in all directions, which then slam into surrounding planets.

Parker is tasked with investigating the mechanics of the breakaway effect and why the atmosphere is so much hotter than its source. “We’ve tried studying these things from Earth, and all of the signatures that we need to see, all the information, gets smeared out over the 93 million miles on the way to Earth,” Eric Christian, the senior research scientist at NASA’s Goddard Space Flight Center, tells The Verge. “We have to go where the action is.”

The mysterious corona

Plans to send a probe into the Sun’s corona date back to 1958 and the very start of NASA. At the space agency’s inception, a special committee listed 14 different missions that NASA should pursue, including visiting all the planets of the Solar System. All 14 missions have been accomplished in some form apart from one: a probe to visit near the Sun.

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